I contacted sony and this is my conversation with them
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Joshua (4/27/2016 6:42:39 PM): Hello, My name is Joshua, how may I assist you today?
Me (4/27/2016 6:42:55 PM): I need your support please
Me (4/27/2016 6:43:18 PM): I have PS4 with 500 gb full of games
Me (4/27/2016 6:43:38 PM): and I need to install another Hard disk 1 tb
Me (4/27/2016 6:43:51 PM): and switching between two Hard disks
Me (4/27/2016 6:44:12 PM): just to remove the screew and place right hd for right games
Me (4/27/2016 6:44:20 PM): is that possible
Me (4/27/2016 6:44:40 PM): to be able to have 1.5 tb of games on two separte HD's
Me (4/27/2016 6:45:02 PM): and just connect the right HD when I want to play a certain game
Me (4/27/2016 6:45:36 PM): I already know how to install the OS
Me (4/27/2016 6:45:50 PM): I will keep the old 500 GB as it is
Me (4/27/2016 6:46:07 PM): and I will install Another fresh OS on the other 1 tb HD
Me (4/27/2016 6:46:38 PM): And I just connect and disconnect each HD With it's own OS
Me (4/27/2016 6:47:10 PM): so I want to know if the OS is stored on internal flash memory or in the HD it's self
Me (4/27/2016 6:47:23 PM): Kindly advice
Joshua (4/27/2016 6:48:09 PM): Hello, I completely understand you wanting to upgrade your hard drive. I actually just did mine because I filled the 500 gb up faster. The OS is installed on the HD itself. When you upgrade it, you can visit our site and download the software onto a USB drive and install it onto the hard drive. Once there though, if you keep swapping out drives, you do not have to keep doing that.
Me (4/27/2016 6:49:14 PM): and If have another PS On my home can I switch between there HD's
Me (4/27/2016 6:49:46 PM): I don't understand you please clarify more
Me (4/27/2016 6:50:11 PM): is it possible to install two separte OS's on two separte HD's
Me (4/27/2016 6:50:25 PM): and working on each one individually
Me (4/27/2016 6:50:33 PM): yes or no
Me (4/27/2016 6:51:04 PM): I know that there is a backup method
Joshua (4/27/2016 6:51:08 PM): When you get a new hard drive and install it, you will have to install the OS on the new one. Once installed though, it will be there unless you delete it. Meaning, you only have to install the OS once per hard drive and if you swap them out, you do not have to do that step anymore.
Me (4/27/2016 6:51:09 PM): but I need to use them both
Joshua (4/27/2016 6:51:39 PM): I apologize there is no way to use both at the same time on the same console if that is what you are asking.
Me (4/27/2016 6:51:49 PM): not at the same time
Me (4/27/2016 6:52:00 PM): not connected at the same time
Me (4/27/2016 6:52:19 PM): I mean I will use the first one then power off the device
Me (4/27/2016 6:52:33 PM): and connect the second one after installing OS on it
Me (4/27/2016 6:52:38 PM): then use it
Me (4/27/2016 6:53:02 PM): not to use both of them at the same time
Me (4/27/2016 6:53:24 PM): just to disconnect the 1st HD and connect the 2nd HD
Me (4/27/2016 6:53:43 PM): and I will download newer games on the 2nd empty HD
Me (4/27/2016 6:54:00 PM): Did you got what I need
Me (4/27/2016 6:54:05 PM): ?
Me (4/27/2016 6:55:01 PM): 1st HD has OS with its games and the second HD has OS with it's own games
Me (4/27/2016 6:55:43 PM): and I will just plug the right HD And power on device without loosing any game or backig up it
Joshua (4/27/2016 6:55:51 PM): Oh yes, I do understand. Yes you can do that as often as you like if you wish.
Joshua (4/27/2016 6:56:14 PM): You will not lose anything and it will be a simple swap since you already have the OS and everything installed and downloaded.
Me (4/27/2016 6:56:48 PM): is it possible to swap HD Between two different PS4 ?
Me (4/27/2016 6:57:19 PM): Or the HD might be encrypted or something like that ?
Joshua (4/27/2016 6:58:26 PM): As long as you do it safely and properly every time, you will not have any issues swapping them out constantly.
Me (4/27/2016 6:58:55 PM): to confirme >>> from TWO Different PS4
Joshua (4/27/2016 6:59:01 PM): What I might suggest though that if you plan on doing that, you might want to look into just getting a 2tb or higher hard drive and putting all your games on the one so you do not have to keep switching.
Me (4/27/2016 6:59:29 PM): ok
Me (4/27/2016 6:59:35 PM): but switching is safe
Me (4/27/2016 7:00:00 PM): even it was with differnt software version or different ps4 ?
Me (4/27/2016 7:00:04 PM): true
Joshua (4/27/2016 7:01:12 PM): I was looking into this and actually if you take a hard drive from a different PS4, it would format the drive and delete everything as it syncs up to the consoles information such as serial number etc. But swapping between two hard drives and one console is perfectly fine.
Me (4/27/2016 7:01:56 PM): swapping between two hard drives and one console is perfectly fine.
Me (4/27/2016 7:02:03 PM): that is what I need to hear
Me (4/27/2016 7:02:11 PM): many thanks
Me (4/27/2016 7:02:30 PM): thanks for your time
Joshua (4/27/2016 7:02:40 PM): You are very welcome! Is there anything else I can assist you with today?
Me (4/27/2016 7:03:36 PM): now I will try and feed you back I wish I did't get any lost games or any confilcts and use both HD's With both OS's smoothly
Me (4/27/2016 7:03:55 PM): thanks again for you time
Me (4/27/2016 7:03:57 PM): bye bye